Piston and method of making the same



Feb. 11, 1930. E. H. POWERS PISTON AND METHOD OF MAKING THE SAME Filed April 2. 1926 2 Sheets-Sheet 1 Gum/144 c gnaw/144 06 Make/21 01061;

2 Sheets-Sheet 2 E. H. POWERS Filed April 2, 1926 PISTON AND METHOD OF MAKING THE SAME Feb. 11, 1930.

Patented Feb. 11, 1930 EDWIJN' H. POWERS, OF SAGINAW, MICHIGAN PISTON AND METHOD OF MAKING THE SAME Application tiled pril 2, 1926. Serial No. 99,387.

The present invention appertains to improvements in pistons, in the art of which many efforts have been made heretofore by which to reduce their weight as well as their cost of production.

In the main, these are the special objects of the improvements hereinafter set forth, these ends being attained not only by a novel construction embod ing a composite body of cast and sheet materials, but also by a novel method of drawing or stamping and molding which shows material economy in manufacturing costs with a superiority of the product.

To this end the present invention is characterized as to novelty by the provision of a piston bod which is composed of a head of cast metal and a skirt of drawn or diestamped light sheet metal, said skirt being built of correspondin cylindrical portions which when conjoine form complemental parts providing an interiorly reinforced section or body with which the cast head peculiarly coacts to afford a distribution of the explosion stresses to be transferred to the connecting rod.

Secondly, an important feature resides in the provision of a skirt so constructed that i the reinforcementlreferred to takes the form of complemental sections serving as wrist pin bearings, the general similarity of the sections of said skirt portion requiring a minimum a number of dies with the resultant material saving in stamping operations.

Other objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claims. 5

In the accompanying drawings:

Figure 1 is a side elevation, partly in section, of a piston body constructed in accordance with my invention Figure 2 1s a vertical sectional view on the plane indicated by the line 2-2 of Figure 1;

Figure 3 is a ottom plan view, showing more clearl the rectangular opening accommodating t e connecting rod;

Figure 4 is a sectional view on the line 4-4 of Figure 1 showing in plan the lower portion of the piston skirt;

Figure 6 is a shown in Figure 5; and Figure 7 is a top plan view of the part side elevation of the skirt unit, after the end flanges have been turned in and ready to receive the die casting, a portion being broken away and shown in section.

Like reference charact ers designate corresponding parts throughout the several figures of the drawing.

Referring to the drawings,

the piston construction of this invention embodies the head portion 1 in which the ring grooves 2 are formed, and the skirt portion 3, the former being of cast material and the latter of sheet material.

I am aware that composite pistons of this general type are not broadly new and I shall therefore guishing .eatures well as their advantages.

In the first place,

oint out hereinafter the distinof these improvements as the skirt portion 3 is composed of two sections which correspond in every particular excepting only as to their length dimension, the

lower section preferably being equal to the length of the up er section plus the head 1. variation will be The reason for t is apparent to those skilled in the art to which this invention relates but in the main it gives rise of the lateral pressures by to an equalization virtue of the disposition of the wrist pin bearings centrally of the piston body.

For either of these skirt sections, therefore, the blank sheet metal is first drawn up into a cylindrical pistonb end, said closed ody, having a closed end being then depressed by the die at opposite sides to produce semicylindrical depressions 4 while the material is pierced or cut away centrally of the end to provide a rectangular opening 5 of a size sufficient to accommodate connecting rod. The ed movements of the ges of this opening are bent inwardly forming an annular flange 6 which greatly strengthens the metal against deformation. Two such 1y longer than the other, now placed end to end as sections, one slightas before stated, are shown in Figures 5 and 7 and spot welded preferably at the points designated 7 as shown in Figure 6, the cylindrical depressions 4 now registering with each other to form the complemental portions of the wrist pin openings. The cyhndrical unit or body thus formed is now arewelded around the abutting joint as indicated at 8 so as to obtain an integral skirt portion. Following this the flanges 9 at the opposite ends of the skirt unit are turned inwardly, thereby providing at these points the proper resistance to deforming stresses.

.The skirt is thus prepared for the casting of the head 1 which, it will be apparent from Figures 1 and 2, is interlocked with the top or short section of the skirt by the end flange 9 thereof. In this operation the mold is so formed as to provide the opposite interior extensions 10 of the head which extend over and abut the upper bearing sectors 4. Such an arrangement, it will be obvious, is important for the taking care of the explosion stresses, relieving the side walls of the skirt to a great extent.

V The piston head 1 may now be machined and the bushings 11 pressed into place, following which the usual grinding of the piston is effected.

It will be apparent from the foregoing that the conjoined ends of the skirt sectlons act in the nature of a bracin web which gives to the body of the piston a equate strength for all purposes and I desire it to be particularly understood that I believe I am the first to form a piston body by conjoining two corresponding sections in the manner hereinbefore set forth. The piston so constructed will necessarily be very light and will possess many other advantages which are well known in connection with composite piston constructions. I

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. A composite piston comprising a cylindrical sheet metal body provided with a transverse web, said web having depressions at opposite sides of the body to form wrist pin bearings and reinforcing means, and a cast head having interlocking connection with an end of the body, said head being provided with extensions coacting with the said bearin s.

A composite piston comprising a skirt portion of sheet material and a head of cast material, said skirt portion being composed of two cylindrical sections having partially closed ends, said ends forming a transverse web shaped to receive a wrist pin and having a flanged opening therein which constitutes a connecting rod opening having flanged edges.

3. A composite piston comprising a cylindrical sheet metal body formed with a transverse web and opposite wrist pin bearings, 

